1. Field of the Invention
The present invention relates to the field of semiconductor device packaging.
2. Prior Art
High power devices require means to conduct high amounts of currents, low RDSon (drain-source resistance when the device is turned on), and means to efficiently remove heat. Also, products using vertical MOSFETs require that electrical contact be made on both top and bottom sides of the structure. Integrating more than one MOSFET may require that current output from one MOSFET be input in series into the second MOSFET while a controller die manages functions of both MOSFETs. In this case, both MOSFETs need to be electrically isolated from each other as well as the controller die.
A QFN package, known in the art, is defined as a “Quad, flat, no-lead” package. The package generally uses a flat lead frame having a central area surrounded by leads that are cut off and separated from the center section, referred to as a pad or paddle, after molding plastic around the packaged device. Solder bumping is used for mounting on the next assembly. The center section may be used as a ground plane, for heat conduction out of the package, or both.